[Dashboards listing] fix listing limit

Initial page size was passed to the search function instead
of the listing limit causing the max amount received to be
significantly less than the previously implementation.

Saved objects per page is `20` by default and the listing
limit per page is `1000` by default.

Issue:
#4017

Signed-off-by: Kawika Avilla <kavilla414@gmail.com>

Author: kavilla

src/plugins/dashboard/public/application/legacy_app.js

@@ -150,7 +150,7 @@ export function initDashboardApp(app, deps) {
               type: $scope.dashboardListTypes,
               search: search ? `${search}*` : undefined,
               fields: ['title', 'type', 'description', 'updated_at'],
-              perPage: $scope.initialPageSize,
+              perPage: $scope.listingLimit,
               page: 1,
               searchFields: ['title^3', 'type', 'description'],
               defaultSearchOperator: 'AND',